Etymon
gem-ankijana-protogermanic-anhtaz-protowest-germanic-aht-old-english-oht-middle-english-thought-english-thought-protoindoeuropean-lewh1-protoindoeuropean-lewhsder
A dedicated page for this root is on the way — it will gather every word descended from it, sibling forms across daughter languages, and a branching map of the family tree.